Method for spinning artificial filaments



1951 J. w. COLEMAN ETAL 2,536,093

METHOD FOR SPINNING ARTIFICIAL FILAMENTS 3 Sheets-Sheet 1 Filed May 28, 1947 l/VVE/V 70/?5. JAME'6 14 COLEMAN JAMES w HALL HOWARD 0. MER/ON SANFORD A. M06$.JR, uo/wv WATSON PEDLOW 1951 J. w. COLEMAN ETAL 2,536,093

METHOD FOR SPINNING ARTIFICIAL FILAMENTS INVENTORS. JAMES w COLEMAN JAMES w HALL HOWARD 0. MER/ON JAN/FORD A.M0.ss.un. 1 4 JOHN WATSON PEDLOW 1951 J. w. COLEMAN EI'AL 2,536,093

METHOD FOR SPINNING ARTIFICIAL FILAMENTS Filed May 28, 1947 3 Sheets-Sheet 5 IIVI/E'NTORS. c/AME'J W COLEMAN JAMES W. HALL HOWARD D MER/ON SANFORD A. M06-S,Jn. JOHN WATSON PEDLOW Patented Jan. 2, 1951 2.53am METHOD ron srmmo ARTIFICIAL mam-m James W. Coleman, Ridley lark, Jamel-W. Hall,

Media, Howard D. Merion, West Chester, Sanford A. Moss, Jr., Bidley Park, and John Watson Pedlow, Chester Heights, Pm, a-ignors to American Viscose Corporation, Wilmington, Del., a corporation of Delaware Application May 28, 1847, Serial No. 75 348 8 Claims. (Cl. 1H)

This invention relates to improvements in methods for spinning artificial filaments. More particularly this invention relates to improvements in methods for spinning artificial filaments wherein filament forming material is extruded into a liquid bath.

In the manufacture of artificial filaments wherein the filament forming material is extruded into a liquid bath, the filament forming material is extruded beneath the surface of the liquid bath and the filaments that are formed are drawn from the liquid bath by a positively driven. roller or other rotary device the peripheral speed of which is a factor in determining the spinning speed. Thereafter the filaments are usually subjected to stretching and liquid treatments.

With the present invention certain spinning procedures and apparatus are employed whereby artificial filaments of high quality and uniform physical properties are produced.

Although the present invention will be described hereinafter largely with reference to viscose regenerated cellulose filaments and the viscose process this is for purposes of illustration and it is to be understood that the invention is also applicable just as well to the spinning of cuprammonium, cellulose nitrate and other filaments where a spinning solution is extruded in a liquid bath and especially where the liquid of the bath carried by the filaments continues to act on the filaments after they have been withdrawn from the bath.

In the production of artificial filaments by the viscose process for instance, a solution of cellulose xanthate is extruded through a spinneret positioned in a regenerating bath generally comprising dilute sulphuric acid, sodium sulphate and other metal salts such as zinc sulphate and the like. The bath chemically reacts with the viscose solution to form filaments or regenerated cellulose. The chemical reaction takes place while the viscose solution and the filaments being formed are passing through the bath and the bath carried by the filaments after they emerge from the bath continues the reaction. The coagulation of the viscose and regeneration of the cellulose comprising a filament first take place in the outer layer of the filament and proceed inwardly. In order to obtain filaments having a certain tensile strength and extensibility the filaments are subjected to a positive stretching step by positively-driven rollers or other rotary devices after a suflicient preliminary set up and regeneration of the cellulose has taken place. The filaments after being stretched are further set up, washed, processed and finally dried.

It was found that with conventional practims although great care was taken to keep the spinning conditions constant by maintaining the bath temperature uniform, recirculating the bath and maintaining its composition uniform, and withdrawing the filaments and stretching them by rotary devices positively driven at uniform speeds, the danger or broken filaments due to the resistance ofi'ered by the spinning bath to the passage of the tender filaments was always present. Eddy currents and other uncontrollable hath fiow induce stresses that influence dyeing 20 and other physical characteristics uniavorably,

irrespective of whether the spinning takes place vertically or horizontally. while these harmful conditions are present at ordinary spinning speeds, at higher spinning speeds these conditions 35 are greatly increased and result in lower quality due to more broken filaments and decidedly lower tensile strengths and extensibilities.

This invention has for its principal object to provide improvements in methods for spinning artificial filaments that overcome objections and disadvantages found in the prior art.

This invention has for another object to provide improvements in methods for spinning artificial filaments that produce filaments or high quality and uniform physical properties.

This invention has for a further object to provide improvements in methods for spinning artificial filaments that produce filaments of high quality, uniform physical properties and improved tensile strength and extensibility.

These and other objects and advantages or the invention will be apparent from the following description and the accompanying drawings.

In the drawing:

Figure 1 is an elevational view with parts shown in section of a form of apparatus for carrying out the present invention.

Figure 2 is an enlarged elevational view of a portion of a form of apparatus similar to that showninFlsureiandinwhichadirectional Figure 4 is an enlarged view ofa portion of the apparatus shown in Figure 3 and comprising the spinneret, draw off wheel and means for collecting the used spinning bath.

Figure 5 is a plan view of the face of a spinneret that may be used in practicing this invention.

Figure 6 is an elevational view showing diagrammatically the bath currents and flow present in conventional spinning of artificial filaments with so-called horizontal immersion.

Figure 7 is an elevational view showing diagrammatically the bath currents and now present in conventional spinning of artificial filaments with so-called vertical immersion.

In accordance with the present invention it was found that artificial filaments of high quality and uniform physical properties could be obtained by practically eliminating all tensile stresses to which the filaments were formerly subjected during the initial stages of filament formation referred to as set up and/or regeneration until the regeneration had proceeded sumciently to permit stretching and then positively stretching the filaments a controlled amount by passing them between a pair or pairs 0f godets or other rotary devices positively driven at successively higher peripheral speeds while maintaining the composition of the spinning bath adjacent the spinneret uniform.

A careful analysis of the spinning procedures usually employed showed that the individual fila ments were subjected to variable bath resistance and stresses before the filaments were toughened by sufilcient set up to withstand such severe and drastic treatment. These variable stresses were dii'ficult, if not impossible, to uniformly control and the physical properties of the filaments produced under those conditions were adversely affected.

It is always desirable in the manufacture of artificial filaments that broken filaments be avoided and that the filaments have uniform dyeing properties. The tensile strength generally measured in grams per denier and the extensibility are also important physical characteristics. I'br certain purposes, such as in crepe yarn, it is desired that k the filaments have a high extensibility while for other purposes, such as tire cord, it is desired that the filaments have a low extensibility ands high tensile strength. For any purpose it is desired that the number obtained by multiplying the tensile strength by the extensibility be high. This number is hereinafter referredto as the quality index.

It was observed that with the usual travel of the filaments through the spinning bath or immersion, appreciable stresses on the filaments becarried along with the filaments after they emerged from the bath. These stresses were not only large but also variable and uncontrollable. There was usually a turbulent condition where the filaments emerged from the bath and a large amount of the spinning bath carried by the filaments ran or dripped oi! the filaments after they had emerged from the bath. In the ordinary spinning procedure the volume of the spinning bath carried by the filaments is determined by such factors as the number of filaments, the

. spacing of the filaments, the size of the filaments,

the length of travel of the filaments in the bath (immersion) and the speed at which they are drawn through the bath. In the usual practice immersions are adjusted merely to provide sufficient set up for subsequent stretching and handling of the filaments.

Figure 6 of the drawing shows diagrammatically the manner in which the bath is moved and swept along by the filaments with a horizontal immersion of the usual length. Figure 7 illustrates this movement of the bath by the filaments where the filaments are spun vertically with the usual immersion length. Both illustrations indicate the large volume of bath being moved by the filaments and the turbulence of the bath where the filaments emerge from the bath and the back flow of the bath along the filaments to demonstrate the work the tender filaments are called upon to perform while still in a semi-viscose condition. This movement of the bath commences immediately at the point where the individual viscose streams emerge from the race of the spinneret. As the rate of drawing the filaments through the spinning bath is increased with the usual immersion length it is found that the stresses imposed on the filaments are increased and at higher speeds the quality and physical characteristics of the filaments are not satisfactory.

The data in the examples in the following Table I show the effect of increases in the speed of the rotary means for drawin the filaments from the bath on the physical characteristics of the viscose artificial filaments that are produced in ordinary viscose process spinning procedures. With increases in speed of the draw 06 means the tensile strength and extensibility of the filaments either wet or dry and the quality indices are decreased. Irrespective of whether yarn is washed and dried immediately on a continuous basis or collected in an acid or washed condition in a spinning box and subsequently treated and dried the same loss in physical properties is experienced when spinning speeds are increased.

TAMI

Example 1 conditions:

150 denier, filament 12" vertical immersion ing spun were caused by the drag of the spinning 25% stretch bath on the filaments and the weight of the liquid us continuously washed and dried l rsw 6i a t? Index ig; Wheel ry Wet Qual. m gJden. t gJden. percent Ind 01. 0 act 21 1.11 20.5 40. 0 an ma 01.0 1.04 11.5 1.00 25.0 00.0 sec can 00.0 1.00 no .00 no 31.1 22.5 00.0 use 2.00 no .00 10.0 02.0 18.5 00.0

. Example 2- Conditions:-

150 denier. 60 filament l2" immersion stretch Collected in spinning ed in skeln form box. washed and treattary set up. Further advantage can be taken of the illsments'desiretoshrinkbyutiliaingasthedraw It was found in accordance with this invention that, ii substantially all tensile stresses on the artificial filaments being spun were eliminated until the filaments were toughened sumciently in the initial set up and the filaments were in condition to be positively stretched. filaments of high quality and having suitable physical characteristics could be spun at normal speeds of the draw all means. around forty to sixty meters per minute, as well as speeds greatly in excess thereof. such as speeds of the order of one hundred twenty to one hundred sixty and more meters per minute. This is efiected by using an immersion length, that is, path of the filaments from the face of the spinneret to the surface of the spinning bath of not more than 2" and more particularly of from 1%" to 56". The filaments pass from the spinneret to a positively driven draw on means such as a sodet, roller, thread store device or the like, the peripheral speed of which is a factor that determines the spinning speed. Using an immersion length of from 1 V to it", the filaments smoothly emerge from the spinning bath without turbulence and substantially all of the spinning bath that is withdrawn by the filaments from the bath is carried in a unii'orm and smooth colunm along with the filaments without any apparent back flow o! the bath along the filaments or dripping oi! the filaments. The path of the filaments from the spinneret to the draw oif wheel may be direct or with only a directional guide means lightly contasting the filaments and the filaments during this travel are subjected to approximately only the tensile stress caused by their own weight and that of the spinning bath that is carried up with them. The filaments may be in contact with the draw oif means for less than 360 of its periphery or may be wrapped in successive turns to provide storage and thus time for additional regeneration of the partially set up filaments. The filaments then pass to the means for positively stretching the filaments. The stretching means may comprise a godet. roller or thread store device positively driven at a speed higher than the draw oil means or spaced godets. rollers, or thread store devices driven at successively increased speeds. The filaments may be subjected to additional spinning bath or other setting up treatment by passing them through a supplementary bath after they pass over the draw oi! means. or spinning bath or other active setting up materials may be applied on a plurality of turns of the filaments on means a thread stora taper corresponding to a 01 the filaments of the or with this procedure t as device which has a relaxation or shrinkage dot of 3 to 5%.

he spinning bath liquid that is carried out or the spinning bath with the filaments does not perceptibly drip ad or flow back along the filaments. but substantially all of the liquid withdrawn by the filaments from the bath remains with the filaments in the form of a uniform column until the filaments contact the directional guide means where one is used or the draw ofi means. to stay on the draw all means to approximately the position where the filaments leave the draw of! meam in passing to the positive stretching means.

In the viscose process the spinning bath that is withdrawn from the bath with the filaments nou products such as water. sodium sulphate, sulfur, thionic acids and gaseous products that ordinarily dilute or contaminate the spinning bath and inhibit the initial setting up reaction. In the present method of spinning as they are formed.

It is found that as the spinneret is moved vertically under the bath from deep to shallower immersi by the filaments is so small able to support the entire tially all of the liquid with with the filaments adheres form of a smooth colum that the filaments are volume and substandrawn from the bath to the filaments in the 1: without appreciable The spinning bath is found a tion of the face and are spaced close together in 5 the same circle and from circle to circle a distance of the order of 0.005 to 0.015 inch. This is shown by the data in Examples 1 and 2 of the following Table III of a viscose spinning procedure.

TABLE III Conditions: Example 1 150 er. 60 filament 5k immersion 30% stretch 8 through the surface the bath when the immerscinoascare at no: less the: said criticmt. mm a 1 2; an a at 9 Ellen P P i denier per filament, nlament count and spacing m 0! holes in the spinneret face. In general, iila- 5 merits of uniform dyeing and good physical 13: 3-3 g-g, 3: 33-; :3 m characteristics can be obtained it immersions are 1.00 1010 010': 2010 e11: air air kept at an amount less than the point where the back flow Ol drip 0c oi the bath from the iila- Conditions: i Z ments starts. This amount of immersion may be m 1 0 deni r. 6 filament called the critical immersion. It has been found it" mm n that dyeing properties of the filaments are uni- Stretch form and the other physical properties are not speed 0! w 1 wh m-8 .5 m-lmlnmaterially ailected at any spinning speed it the load on each filament carrying bath in the form is m Hole Spacing w l m n 0! a smooth column from the surface of the 500 2120? 00m spinning bath to the draw on wheel does not Circle! Hole] Minn Column Inch" exceed 0.002 to 0.0025 gram per inch of length but is preferably in the range from 0.00025 to 0.0015 gram per inch of length. 20 a; g'g 6% gw This invention is not limited to spinning any M m 1. 6 01090 010010 particular number of filaments, or a yarn having M30 M30 any particular number of filaments. The larger the number of filaments that are spun from the Qua] Index same spinneret, the greater the quantity of 95 a: 53 3:, $3 83? spinning bath that is drawn up with the nlag-Idei'i. Pemi'n 0406i rerei'ii Dry we mini ments. However, the load on each filament remains virtually constant and the usual loss in 8 31 5M 3 no physical properties is not found in this method 107 32 MI! 21 45 5 27-8 73.3 .o! spinning. Using an immersion less than the 3 critical amount, not more than 2" and preier- The data in the follow T b ably 1%" to ye"- Satisiflctory pi ning condlresults of spinning 150 derail, 01300228203: 610115 and filaments are Obtained- This is Bhflwn with selected immersion lengths at a draw of! by the data set forth in the following Table 11. speed of 97.5 meters er minute, using a spinneret Thi da a app to viscose re e e a ed cellulose 35 with 0.005" hole to hole and circle to circle yarn oi 150 denier and to a speed of the draw oi! spacing, n; 1 shown t a critical t, 5 wheel of 112.5 meters per minute with a V4" reached where the immersion length is approxiimmersion but similar beneficial results are obmately 2 inches. Immersion lengths greater than tained at other deniers and higher or lower spinthis are shown to have a marked effect on the hing speeds. extensibility and tensile strength of the filaments.

TABLE II Lead on BL No. Fila- 8:13:3 23 0? 3 1 253 g t l nder Combined merits By Yarn, Column in. Yarn Length woe-6t g0 EIL- unlcc./mln. inmm. inGrams Gram 8-! 611- D c n y wet Index e0 m 1.0 0.002 .000! an 20 1.10 00 44. 04.5 78.5

as 1.1 .014 .00002 2. i 20. e. 004 1.0 3.000 .00014 2% 1: i120 g 1: 1:

Improved results may be obtained in the prac- TABLE IV tice 0! this invention by using spinnerets in which the holes are grouped together at the central por- Conditions:

.150 denier, 60 filament viscose regenerated cellulose yarn stretch Spinneret-fiil hole with 0.005" hole to hole and circle to circle spacing Speed or draw on wheel-97.5 m./mln.

v01. Bath Dla.ol w i m Immer- Carried Bath of 501] E slon By Yarn, Column, In. Yarn, fi t g ccJmin. in mm. in Grams Inches l6 :0 0.10 0. 010 0. 00001 n 00 0.10 0.020 0. 00034 a as 0.0a 00% 0.00008 01 1.05 0.033 0.00055 1 101 1.10 0.000 0.00050 m 110 ms 0.040 0.00000 1 200 1.05 0.020 0.0011 2 840 2.05 0115 011092 a m 2.20 0:42 0.00240 4 s 0 s00 Index Dry Dry Wet Wet, QM Combined Sta, Ext, Sta, Ext, Qual. lJdeu. percent gJden. percent Dry wet Index 218 %.6 1.14 82 60 30.0 80.6 2. l 34. 0 l. 33 00 30. 5 80. 8 1.00 24.0 1.15 34 60 30.6 80.6 3.14 23.0 1.13 84 50 30.5 8H5 2.10 H. 0 l. 18 32 48 30. 0 84. 0 2.07 20.5 1.12 30 43 34.0 77.0 2. 1s :1. u 1. 13 32 4s 38. s s]. 5 2.10 22. s 1.10 so 41 35.0 82.0 2. (B 17 l. 00 22 36 2!. 6 00. 6 2. l0 17 l. 12 23 00 2!. 5 02. 0 3. 08 16 l. 11 22 34 iii. 0 00. 0

Another example oi the eil'ect of immersion lengths is shown in the following Table V in spinning 150 denier, 60 filament count viscose regenerated cellulose yarn at a draw ofl speed 01' 105 meters per minute. Here the spinneret hole spacing is 0.01" hole to hole and circle to circle. A critical point is reached at approximately 7 immersion. At immersions longer than this a decided drop in extensibility and strength is noted. At immersions longer than 2" the results are erratic due to uncontrolled back flow oi bath carried by the filaments and bath drag.

TABLE V Conditions:

150 denier. 60 iliament 30% stretch Speed of draw on wheel-105 mJmin.

Vol. Bath Dis. 01 Weight 9' Immer- Carried Bath oi Bath! f sion By Yarn, Column, In. Yarn, i

ccJmin. in mm. in Grams Gm Inches g 145 l. 3 D. 045 0. m

205 l. 5 0. 055 0- 001 M 245 1. 7 0. 077 0. M12 '4 290 1. 9 0. 002 0. 115 335 2. 0 0. 1m 0. W17 1 412 2. 2 D. 130 0. 002! 15 430 2. 3 0. 136 0. 0022 l 460 2. l 0. 145 0. 0021 122 500 a 5 15s 0. 0026 1 540 2 55 0 170 0. 0028 I? 500 4 A 2 3 4 5 6 Dry Dry Wet Wet. Combined Btr., Ext... Str. Ext, Qua]. gJden percent gJden percen Dry wet Index 2.15 19.5 1.16 28 42 32.5 74.7 2. 1 21 1. 15 29 H 33. 4 77. 0 2. 2' 21 l. 17 28 46 32. 8 78. B 2. 2 21 1.15 28 46 32. 2 78. 2 2. 1 1. l 2'] 42 29. 8 TI. 8 2. 15 20 1. 0B 43 26. 5 69. 0 2.1 18. 5 1. 0'5 24 39 25. 2 54. 2 2. 15 18 l. 07 25 39 27. 8 56. 8 2.1 18. 5 1.05 25 39 26.3 55.3 2- 17.5 1.0 23.5 36 23.5 59.5 2.0 17. IJB 23 34 2L7 57.7 2.15 18 1.05 KB 39 24. 2 53.2 2. 0 17 I. w 22 31 23. 3 57. 3 2 0 17 1. 0 22 34 22. 0 56. 0 2. 05 I9 1- 05 23 3Q 23. l 62. 1 2. 1.1 19 l. 0 23 40 23. U 63. 0 2 2 1B 1. l 22 40 24. 2 54. 2 2. I 17 l. M 20 3B 20. 8 56. a 2. 1 17 1- 08 20 36 21. B 57. 6

The following 'Ihble VI shows the effect of immersion lengths when spinning 150 denier, 40 filament count using a spinneret with 0.010" hole to hole and 0.010" circle to circle spacing and with the speed oi the draw oi! wheel 97.5 meters per minute. In this case a critical point is reached at approximately V At greater immersion depths the back flow and increased drag of the bath have a deleterious efl'ect on the extensibility and tensile strength or the filaments.

TABLE VI Conditions:

150 denier, 40 filament viscose regenerated cellulose yarn 35% stretch Speed of draw on wheel-97.6 m./min.

Vol. mu. Din. of Weight W Immer- Carried mm of Bath] a: sion By Yarn, Column, In. Yarn, Length ocJmin. in mm. in Grams Inch-u 1w 1. 2i 0. 044 0. 0011 215 l. 00 0. 073 0. (1117 m l. 0. 008 0. M24 1 305 2. 2 0. 133 0. 033 l 470 2. 4 0.150 0. 040 l 4!) 2. 3 0.145 0. 030 2 415 2. 26 0. 140 0. 036 5 2. i 0. 113 0. 028

Dry Dry Wet Wet, Combined Sta, Est, Sta, Ext Qual. g./den. percent gJden. percent Dry wet Index 2.17 1L5 1.13 3 44.5 31.7 70.2 2.10 an 1.17 20.5 43.8 31.0 7L8 2.08 17.5 1.12 25.0 36.5 8.0 64.5 2.13 [7 I. 10 2% 35. 2 25. 3 81. 5 2. 09 l5. 5 1. I0 22. 5 32. 4 24. 7 57.1 2.13 14.5 1.09 33.5 30.8 22.4 53.3 2.13 10.5 1.07 21.0 33.0 22.5 55.5 2. 18 14.5 1.12 19.0 31.0 21.3 52.0

The following Table VII shows the eilect of immersion lengths when spinning denier, 40 filament count using a spinneret with a 0.010" hole to hole and 0.010" circle to circle spacing and with-a draw oil speed of 97.5 meters per minute. Here the critical point is reached when the immersion length is approximately 34''.

TABLE VII Conditions:

100 denier, 40 filament viscose regenerated cellulose yarn 35% stretch Speed of draw of! wheel-97.5 m./min.

Load on Vol. Bath Dis. oi Weight Immer- Carried Both of Bath; 2 2 3 on By Yarn, Column, In. Yarn,

ocJmin. in mm. in Grams Gmm's 5 m 1. as o. 051 0. 001: 5 220 1.05 0.016 0.0019 5 aos 1.0a 0.10s 0.002s 323 25:; 3'33 8%? 1 1% m 2. 2s 0. 142 0. was 2 4m 2. 20 o. a can 3 can. 215 0.129 0 one: 4 can 2 15 a 12s cone: s 400 2. so a 135 a cum some This invention may be carried out with either pot or bobbin spinning or may be carried out with a continuous process where the filaments after being positively stretched are collected on thread storage reels and subjected to further liquid treatment and drying.

Referring to Figure 1 of the drawing in which a form of apparatus is shown whereby. the invention may be carried out, reference character I indicates generally a trough containing a spinning bath in which is positioned a spinneret 2 mounted on a suitable rounder 3 or other suitable connection to a source of spinning solution. As shown the rounder passes through the bottom of the spinning trough through a seal which permits the spinneret to be positioned at selected distances below the surface of the spinning bath although other forms of rounder may be used. The filaments that are formed in the spinning bath are drawn upwardly through the bath to the positively driven draw oi! wheel I which is rotating in the direction shown by the arrow and remain in contact therewith for at least a portion of its periphery. The filaments lightly contact the directional guide means 5 positioned above the spinneret and between the surface of the bath and the draw ofl' wheel. The guide means may be either rotatable or stationary and is inclined with respect to the horizontal so that any liquid removed from the filaments by the guide means will run along the guide means and away from the path of the filaments and may be collected. The speed of the wheel is a measure of the final spinning speed. As shown the spinneret is positioned relatively close to the surface of the spinning bath so that the immersion length is short, not more than two inches and preferably between 1%" and /8. The draw 01! wheel may be rotated at normal peripheral speeds around 40 to 60 meters per minute as well as speeds greatly in excem thereof such as speeds of the order of 120 to 160 meters and more per minute. The filaments emerge from the bath without any turbulence at the surface of the bath and substantially all of the liquid withdrawn from the bath by the filaments is carried upwardly by the filaments without drip or back flow. The filaments pass from the draw of! wheel to the positive stretching means which, as shown, comprises the positively driven godets B and Ill, the godet it being driven at a higher speed than the godet t. In those cases where it is desired to subject the filaments to a subsequent setting up treatment such as spinning bath, hot water or dilute acid the trough member I is provided. While the draw ofi wheel l may be slightly fluted in order to draw the filaments upwardly, the filaments are free to shrink in passing from the, spinneret to the godet 8 either on the draw of! wheel and/or after leaving the wheel. To enable the filaments to shrink on the wheel. the wheel may be tapered, with the filaments passing over the wheel a plurality of times from the larger end toward the smaller end. To eliminate stresses on the filaments in excess of any bath drag and to permit further relaxing of the filaments. when the filaments are subiected to liquid treatment, such as in the trough-like member 1, the godet may be driven at slightly lower speed than the draw of! wheel 4.

In the form of apparatus shown in Figure 2 of the drawings, the parts and their arrangement are substantially the same as in the apparatus shown in Figure 1 except that the filament directional guiding means I is between the surface of the bath and the draw on wheel and laterally spaced from the spinneret. The guide means may be either rotatable or stationary and may be inclined with respect to the horizontal so that any liquid removed from the filaments by the guide means will run along the guide means and away from the path of the filaments and may be collected. The path of the filaments through the spinning bath from the spinneret it which is the same as the spinneret 2 shown in Figure l is short. not more than 2" and preferably from Y to 1%". Liquid is withdrawn from the bath and carried by the filaments without drip or back flow along the filaments.

Referring to Figure 3 of the drawing in which another form of apparatus is shown whereby the invention may be carried out. reference character it indicates generally a trough containing a.v

spinning bath in which is positioned a spinneret I! mounted on a suitable rounder It or other suitable connection to a source of spinning solution. As shown the rounder passes through the bottom of the spinning trough through a seal which permits the spinneret to be positioned at selected distances below the surface of the spinning bath although other forms of rounder may be used. The filaments that are formed in the spinning bath are drawn directly upwardly without the use of guides or the like to the positively driven draw oil wheel 24 which is rotating in the direction shown by the arrow and remain in contact therewith for at least a portion of its periphery. The distance between the bath surface and the point of contact of the filaments with the wheel indicated by reference character H in Figure 4 of the drawing may be from 6 to 30 inches but is preferably in the range of 12 to 18 inches. The speed of the wheel is a measure of the final spinning speed. As shown the spinneret is positioned relatively close to the surface of the spinning bath so that the immersion length is short. not more than two inches and preferably between 1 and V The draw oil wheel may be rotated at normal peripheral speeds around to meters per minute as well as speeds greatly in excess thereof such as speeds of the order of to meters and more per minute. The filaments emerge from the bath without any turbulence at the surface of the bath and substantially all of the liquid withdrawn from the bath by the filaments is carried upwardly by the filaments without drip or back flow until the filaments contact the draw of! wheel at the position shown by reference character It. The spinning bath tends to remain with the filaments on the draw of! wheel until the point where the filaments leave the draw of! wheel shown by reference character it. The liquid is thrown off the wheel by centrifugal force at substantially this point and is collected in the trough-like membcr ii that surrounds a portion of the bottom of the wheel and the side opposite the side to which the filaments are directed from the bath. The spinning bath collected in the trough il maybesentbythepipefl toabathreclaim or may be discharged as waste. The filaments pass from the draw oil wheel to the positive stretching means which, as shown, comprises the positively driven godets II and II. the godet 2| being driven at a higher speed than the godet II. In those cases where it is desired to subject the filaments to a subsequent setting up treatment such as spinning bath. hot water or dilute acid the trough member I! is provided. While the draw ofi wheel 24 may be slightly fluted in order to draw the filaments upwardly, the filaments are free to shrink in assing from the spinneretto the godet I! either on the draw oil wheel and/or after leaving the wheel. To enable the filaments to shrink on the wheel. the wheel may be tapered. with the filaments passing over the wheel a plurality of times from the larger end toward the smaller end. To eliminate stresses on the filaments in excess of any bath drag and to permit further relaxing of the filaments. when the filaments are subjected to liquid treatment, such as in the trough-like member it. the godet is may be driven at slightly lower speed than the draw oi! wheel 24.

The filaments emerge from the spinning bath and move directly to the draw oii wheel. path of the filaments may be vertical or inclined to the vertical so long as the path of the filaments from the spinneret to the draw oi! wheel is direct. straight and free and guide means are not used.

In Figure 5 of the drawing is shown a plan view of the face of the spinneret that is found useful in the practice of this invention. In this spinneret the holes are grouped close to the center of the spinneret with the distances between the holes in the same circle shown by reference character A and that between holes in adjacent circles shown by reference character B kept to the minimum allowed in the manufacture of the spinneret. It is found in actual practice that preferred results are obtained where these dimensions are of the order of 0.005 to 0.015 inch.

In general this invention comprises spinning artificial filaments by extruding filament forming material into a liquid bath and drawing the filaments from the bath to a draw of! means with substantially no tension on the filaments. The invention is practiced with an immersion length, speed of the draw oif means. distance of draw ofi means to the surface of the spinning bath and spacing of the holes in the spinneret such that spinning bath is carried by the ills.- ments out of the bath with substantially no appreciable back fiow along the filaments or drip oi the bath from the filament after they have emerged from the bath.

With this procedure, it is preferred that the immersion depth, speed of draw of! and spacing of holes in the spinneret be such that the load of spinning bath carried by each filament alter leaving the spinning bath does not exceed from 0.002 to 0.0025 gram per inch of length per filament between the point of contact oi the filaments with the draw oil wheel and the surface oi the spinning bath and is preferably between 0.00025 and 0.0015 gram per inch of length per filament.

With the short immersions described in this invention it is possible to spin at bath temperatures greatly in excess of those normally used. As the filaments emerge from the spinneret and can be lifted by a simple hook, the operators do i4 notsubiecttheirhandatotheharmfulefiectl oi the spinning bath.

Because of the short path of travel of the filo ments through the bath, viscose regenerated cellulose filaments may be spun in a spinning bath at a temperature up to '15 C. and above. In the short period the filaments are in the hot bath the hot bath does not have a harmful efi'ect on the filaments.

While preferred embodiments of the invention have been shown it is to be understood that changes and variations may be made without departing from the spirit and scope of the invention as defined in the appended claims.

We claim:

l. The method of producing artificial filaments comprising continuously extruding streams of filament-forming material with the centers of adjacent streams spaced between 0.005 and 0.015 inch apart into a liquid coagulating bath wherein the streams of filament-forming material produce by-products in their vicinity as they are coagulated to form a bundle of filaments, drawing the filaments as they are coagulatcd upwardly in a straight free path through the coagulating bath a distance up to two inches and then through space to a position above the bath, removing lay-products from the coagulating bath as they are produced, by forming by-products containing coagulating liquid of the bath in the vicinity of the traveling filaments into a smooth continuous column of liquid weighing up to 0.0025 gram per inch per filament flowing entirely under conditions of viscous flow from the surface of the bath with and around the filament bundle to said position above the bath, removing by-products containing liquid from the filament bundle at said position above the bath, collecting the liquid as it is removed from the filament bundle, directing the removed liquid away from the coagulating bath, and stretching the filament bundle.

2. The method of producing artificial filaments comprisin continuously extruding streams of filament-forming material with the centers of adjacent streams spaced between 0.005 and 0.015 inch apart into a liquid coagulating bath wherein the streams of filament-forming material produce lay-products in their vicinity as they are coagulated to form a bundle of filaments, drawing the filaments as they are coagulated upwardly in a straight free path through the coagulating bath a distance up to two inches and then through space to a position above the bath, removing by-products from the coagulating bath as they are produced, by forming by-products containing coagulating liquid of the bath in the vicinity of the traveling filaments into a smooth continuous column of liquid weighing up to 0.0025 gram per inch per filament flowing entireiy under conditions of viscous fiow from the surface of the bath with and around the filament bundle to said position above the bath, removing by-products containing liquid from the filament bundle at said position above the bath by centrifugal force, collecting the liquid as it is removed from the filament bundle, directing the removed liquid away from the coagulating bath, and stretching the filament bundle.

3. The method of producing artificial filaments compirsing continuously extruding streams of viscose with the centers of adjacent streams spaced between 0.005 and 0.015 inch apart into a dilute acid coagulating bath wherein the streams of viscose produce reaction products in assaoes their vicinity as they are coagulated to form a bundle of filaments, drawing the filaments as they are eoagulated upwardly in a straight free path through the coagulating bath a distance up to two inches'and then through space to a position above the bath, removing reaction produots from, the coagulating bath as they are produced, by forming reaction products containing coagulating liquid oi the bath in the vicinity of the traveling filaments into a smooth continuous column of liquid weighing up to 0.0025 gram per inch per filament flowing entirely under conditions oi viscous flow from the surface of the bath with and around the filament bundle to said position above the bath, removing reaction products containing liquid from the filament bundle at said position above the bath by centriiugal force. collecting the liquid as it is removed irom the filament bundle, directing the removed liquid away from the coagulating bath, and stretching the filament bundle.

4. The method of producing artificial filaments comprising continuously extruding streams of viscose with the centers of the adjacent streams spaced between 0.005 and 0.015 inch apart into a dilute acid coagulating bath wherein the streams or viscose produce reaction products in their vicinity as they are coagulated to form a bundle of filaments, drawing the filaments as they are coagulated upwardly in a straight free path through the coagulating bath a distance of from V; to 1% inches and then through space to a position above the bath, removing reaction products from the coagulating bath as they are produced, by forming reaction products containing coagulating liquid of the bath in the vicinity of the traveling filaments into a smooth continuous column of liquid weighing up to 0.0025 gram per inch per filament flowing entirely under condtions of viscous flow from the suriace oi the bath with and around the filament bundle to said position above the bath, removing reaction products containing liquid from the filament bundle at said position above the bath by centrifugal force, collecting the liquid as it is removed from the filament bundle, directing the removed liquid away from the coagulating bath, and stretching the filament bundle.

5. The method of producing artificial filaments comprising continuously extruding stream oi viscose with the centers of the adjacent streams spaced between 0.005 and 0.015 inch apart into a dilute acid coagulating bath wherein the streams of viscose produce reaction products in their vicinity as they are coagulated to form a bundle of filaments, drawing the filaments as they are coagulated upwardly in a straight free path through the coagulating bath a distance of from V; to 1 inches and then through space to a position above the bath, removing reaction products from the coagulating bath as they are produced, by forming reaction products containing coagulating liquid 01' the bath in the vicinty of the traveling filaments into a smooth continuous column of liquid weighing from 0.00025 to 0.0015 gram per inch per filament flowing entirely under conditions of viscous flow from the surface of the bath with and around the filament bundle to said position above the bath, removing reaction products containing liquid from the filament bundle at said position above the bath by centrifugal force, collecting the liquid as it is removed from the filament bundle, directing the removed liquid away from the coagulating bath. and stretching the filament bundle.

6. The method of producing artificial filaments comprising continuously extruding streams of viscose with the centers of adjacent streams spaced between 0.005 and 0.015 inch apart into an acid coagulating bath wherein the streams of produce reaction products in their vicinity as they are coagulated to form a bundle of filaments, drawing the filaments as they are coagulated upwardly in a straight free path through the coagulating bath a distance up to 2 inches and then through space to a position above the bath, removing reaction products from the coagulating bath as they are produced, by forming reaction products containing coagulating liquid of the bath in the vicinity oi the traveling filaments into a smooth continuous column of liquid weighing up to 0.0025 gram per inch per filament flowing entirely under conditions of viscous flow from the surface of the bath with and around the filament handle to said position above the bath, and remo ing reaction products containing liquid from the filament bundle at said position above the bath.

7. The method of producing artificial filaments comprising continuously extruding streams of viscose with the centers of adjacent streams spaced between 0.005 and 0.015 inch apart into an acid coagulating bath wherein the streams of viscose produce reaction products in their vicinity as they are coasulated to form a bundle of filaments, drawing the filaments as they are coagulated upwardly in a straight free path through the coagulating bath a distance of from to 1% inches and then through space to a position above the bath, removing reaction products from the coagulating bath as they are produced, by forming reaction products containing coagulating liquid of the bath in the vicinity of the travcling filaments into a smooth continuous column oi liquid weighing up to 0.0025 gram per inch per filament flowing entirely under conditions of viscous fiow from the surface of the bath when and around the filament bundle to said position above the bath, and removing reaction products containing liquid from the filament bundle at said position above the bath.

8. The method of producing artificial filaments comprising continuously extruding streams oi viscose with the centers of adjacent streams spaced between 0.005 and 0.015 inch apart into a coagulating bath wherein the streams of viscose produce reaction products in their vicinity as they are coa'gulated to form a bundle of filaments, drawing the filaments as they are coagulated upwardly in a straight free path through the coagulatin bath a distance of from 56 to 1% inches and then through space to a position above the bath, removing reaction agulating bath as they are produced, by forming reaction products containing coagulating liquid of the bath in the vicinity of the traveling filaments into a smooth continuous column of liquid weighing from 0.00025 to 0.0015 gram per inch per filament flowing entirely under conditions of viscous fiow from the surface of the bath with and around the filament bundle to said position above the bath, and removing reaction products containing liquid from position above the bath.

JAMES W. COLEMAN. JAMES W. HALL. HOWARD D. MERION. SANFORD A. MOSS, Ja. JOHN WATSON PEDLOW.

(References on following Pm) products from the 00-.

the filament bundle at said 17 REFERENCES CITED Number The following references are of record in the 2,229,092 file of this patent. 23"555 UNITED STATES PATENTS .a 465,408 Number Name Date 1,683,200 Lllienteld Sept. 1, 1928 18 Name Date Lmenfeld Aug. 25. 1931 Kline et a1 Jan. 21. 1941 Jones Feb. 15, 1944 Webb et. a1. Mar. 29, 1949 

1. THE METHOD OF PRODUCING ARTIFICIAL FILAMENTS COMPRISING CONTINUOUSLY EXTRUDING STREAMS OF FILAMENT-FORMING MATERIAL WITH THE CENTERS OF ADJACENT STREAMS SPACED BETWEEN 0.0005 AND 0.015 INCH APART INTO A LIQUID COAGULATING BATH WHEREIN THE STREAMS OF FILAMENT-FORMING MATERIAL PRODUCE BY-PRODUCTS IN THEIR VICINITY AS THEY ARE COAGULATED FO FORM A BUNDLE OF FILAMENTS, DRAWING THE FILAMENTS AS THEY ARE COAGULATED UPWARDLY IN A STRAIGHT FREE PATH THROUGH THE COAGULATING BATH A DISTANCE UP TO TWO INCHES AND THEN THROUGH SPACE TO A POSITION ABOVE THE BATH, REMOVING BY-PRODUCTS FROM THE COAGULATING BATH AS THEY ARE PRODUCED, BY FORMING BY-PRODUCTS CONTAINING COAGULATING LIQUID OF THE BATH IN THE VICINITY OF THE TRAVELING FILAMENT INTO A SMOOTH CONTINUOUS COLUMN OF LIQUID WEIGHTING UP TO 0.0025 GRAM PER INCH PER FILAMENT FLOWING ENTIRELY UNDER CONDITIONS OF VISCOUS FLOW FROM THE SURFACE OF THE BATH WITH AND AROUND THE FILAMEANS BUNDLE TO SAID POSITION ABOVE THE BATH, REMOVING BY-PRODUCTS CONTAINING LIQUID FROM THE FILAMENT BUNDLE AT SAID POSITION ABOVE THE BATH, COLLECTING THE LIQUID AS IT IS REMOVED FROM THE FILAMENT BUNDLE, DIRECTING THE REMOVED LIQUID AWAY FROM THE COAGULATING BATH, AND STRETCHING THE FILAMENT BUNDLE. 